The present invention relates to digital-to-analog converters, and, more particularly, to a delta-sigma digital-to-analog converter incorporating a multiplication function.
Digital-to-analog (D/A) and analog-to-digital (A/D) converters are widely used for converting electrical signals between digital and analog formats. Communication systems, for example, typically require extensive D/A and A/D conversion for performing a variety of signal processing functions. These converters may be implemented on an integrated circuit, such as an application specific integrated circuit (ASIC).
In an ASIC implementation, a converter may be combined with several other signal processing functions for performing the desired ASIC function. One common function implemented on such an ASIC is a multiplier function. There are several known techniques for providing a multiplier on an ASIC. While implementation of a multiplier is well understood and standard multiplier fabrication methods exist, the multiplier typically requires a relatively large area of the semiconductor chip on which the ASIC is formed. As a result, the multiplier typically consumes a significant amount of power.
A delta-sigma converter consistent with the invention includes a feed-forward path for receiving a feed-forward signal and providing an output signal; and a feedback path comprising a multiplying mapping function. The mapping function is configured to multiply the output signal based on at least one multiplication factor and to provide a feedback signal representative of the multiplied output signal. The feedback signal is combined with an input signal to provide the feed-forward signal. A method of multiplying a digital signal consistent with the invention includes coupling the digital signal as the input signal to a delta-sigma converter consistent with the invention.
A digital-to-analog converter consistent with the invention includes a delta-sigma converter configured to provide a digital output signal representative of an N-bit digital input signal multiplied based on at least one multiplication factor; and a digital to analog converter for providing an analog output signal representative of the digital output signal.